Wobbler drive mechanism



June`27, 1950 s. B. EcKERT WOBBLER DRIVE MECHANISM Filed May 24, 1945 :ssheets-sheet 1 June 27, 1950 s. B. ECKERT 2,513,083

WOBBLER DRIVE MECHANISM Filed May 24, 1945 3 Sheets-Sheet 2 Wir/V555.'

@Mx/f June 27, 1950 s. B. EcKER'r 2,513,083

woBBLER DRIVE MECHANISM Filed May 24, 1945 3 Sheets-Sheet 3 PatentedJune 27, 1950 UNITED STATES PATENT OFFICE 2,513,083 WOBBLER DRIVEMcHf-NISM Samuel B. Eckert, Haverford, Pa. Application May 24, 1945K',seriaiNo. "595,593

It is Well understood that within reasonable limits increasing thecompression ratio of an internal combustion engine greatly improves itspower output and fuel efficiency. If, however, such an engine isdesigned for a compression ratio of- (say) 7 to 1 and is then operatedunder normal conditions `with the buttery valve only partially open, the.average compression ratio at which the engine operates is only aboutonequarter of its full capacity. It has Ibeen calculated, as well asdetermined by experiment, that with such reduction in compression ratiothe eliciency of the engine is reduced approximately one-half, involvingserious waste of fuel.

The object of my invention is to adjustably Vary the stroke of thepiston (thereby varying the charge admitted to the cylinder) and at thesame time maintain constant the ratio of volumes of the cylinder at thetwo end strokes of the piston; that is, to maintain, at al1 loads, aconstant compression ratio and hence uniform maximum eiiciency and fueleconomy.

The invention is embodied in an engine of the so-called cranklessopposed piston type, in which adjusting means are provided to (l) varythe position of the piston at the end of its instroke to thereby varythe charge of combustible 'gases admitted to the cylinder and (2) at thesame time vary the length of the stroke of the piston so that the chargedrawn into the cylinder will always be compressed to the samepredetermined pressure.

A preferred embodiment of the invention is shown in the drawings, inwhich- Fig. 1 is a longitudinal view, partly in section,

of the engine.

vFig. 2 is an enlarged longitudinal sectional view of the mechanism,including the piston-stroke adjusting device, between the pistons andthe main driving shaft.

Fig. 3 is a cross-.sectional View on the line 3.-3 of Fig. 2.

Fig. 4 is a cross-section on the line 4 4 of Fig'. 2.

Fig. 5 is a diagram showing how the desired compression ratio may bemaintained at dierent adjustments controlling piston stroke.

The engine is, as hereinbefore stated,.of the opposed piston type andcomprises cylinders a, Within each of which reciprocates opposedpistonsb. No mechanism is shown for actuating the inlet. and exhaustrvalves lz' since these may be ofthe conventional type actuable :by theconventionaltype of half timeV camshaft and valve lifts. IElachl pistonis. through. a connecting rod. cg. at-

5 Claims. (Cl. 74;-60)

taches-l', through `'a universal joint, with a collar or wobbl'erelement d at `the corresponding er-l'cl-v of the engine. This collar isU-shaped in cross-sec'- tion and embraces the periph-eral portion ofarotatable Clisi?v '9.

On an enlargement g of the hollow main driv# ingl shaftjy (see Fig. 2)'are slidable two sleeves i and'v i. lExtending through longitudinalslots k in the enlarged part g of the shaft 'j 'are' cross'- hea'ds mand n secured to the sleeves i and j respectively. These sleeves arethus made to rotate with the shaft.Y The cross-heads are machinefinishedso that they may freelyA move through the stot lc, but lcannot rotaterelative tothe shaft. The disc e is pivoted, at its center, 'to the'crosshead lTo the sleeve 7' is secured a'n arm o and to the disc e issecured anA arm p, these armsv be"- injg connected' by alink r.

Secured to each collarv d are pins t slidable a slotted arm. secured tothe engine casing, thereby neutralizing the tendency of the colla-r d torevolve with the disc e.

From the foregoing description it will be understoody thatreciprocationo'f the pistons effects rotation 'ofthe disc e, cross-headsm, n, sleeves 1' and the mainfdrive. shaft f. y. 1

The centers ofv crosslheads ym, n; are threaded to receivethescrew-threaded portions o andtv; respectively, 'of a shaft s` that"eiftends'through' th hollow, main drive shaft. `Shaft `s isdri'ven froma small controllable motor yg. which is controlled from the throttlen'ot shown). ,The t'l'ireadsv D and w are of different pitch, the threado beine of steeper pitch; soi, that, when the shaft s isfrutatedvn. onedirection or the otl'1e1'-, while 'both cross-heads are moved in thesame'direction, one will4 mIQYe a further; distance thanthe other. Thee'ect; will be. to. swing 4the 'disc e on its pivot in one or theotlrie'i direction,therebyincreasing or reducing the length of.l strokeof the pistons. The shafts may be h elfd? in place by any suitablemeans, kfor example,r by a thrust collar z, a secured' to the shaft. i y

All the mechanism hereinbefore described is duplicated at both end-s ofthe v engine, the. only difference -loeingf thatwthe two pairs: ofthreads. at ormositet ends of, the shaft s; are respectivelyrigjfhthandV and left; hand; threads:,.so that, when; the shaft ys is;rota-'ted one` oli-reation;` or the other, theV two vdiscsl will; ibeswung in, opposite direcL tions. y

The-threadiio is. 'of larger diameter thanthe threadawi.sorth-atwhenthecross-head m is.'moved such: distance; towardf` theL crosseheadi `as.ltot sur;

not engage the thread on cross-head m.

From the foregoing description it will be understood ythat the pitch of`each of the threaded portions of shaft s is so arranged as to insure psuch movement of the disc e as will vary the volume of combustible gasesadmitted into the cylinders a. and at the same time insure that in thereciprocation of the pistons the compression space is varied in such away as to maintain the same compression ratio regardless `of the volumeof the charge taken into the cylinder. This will be clearly understoodby reference to Fig. 5. In this figure the discs e are adjusted, asshown in full lines, to allow a relatively Along stroke of the pistonstively large charge. The distance between the pressure face of eachpiston and the `midway point of the cylinder is shown, at the outstroke,as adistance of 6 units of measurement and at the instroke as l unit ofmeasurement, giving a3 compression ratio of 6 to 1. When the. disc isadjusted to the dotted line position to thereby admit a smaller charge,the distances between the pressure face of each piston and the midwaypoint of the cylinder are reduced (for eX- ample) to 3 units attheoutstroke and 71/2 unit at the instroke,l giving the same compressionratio of 6 to 1. This ratio is maintained constant regardless of thepredetermined length of stroke of the piston.

It will be understood that my improved construction isk sharplydistinguishable from' constructions that are adapted to be adjusted tovary the compression ratio through varying the length of stroke, myimprovement being intended and adapted to avoid any variation in thecompression ratio, that is, vto maintain con-` stant the relationshipbetween the volume of the cylinder with the piston at the bottom of itsstroke' and the volume ofthe cylinder with the piston at the top of itsstroke, thereby enabling the engine to at all times operate at maximumefficiency and economy.

.What Iclaimand desire Patent is: v

1. In an internal ycombustion engine comprising'a rotatable engineshaft, two sets of opposed cylinders disposed about said shaft andhavingtheir axes parallel thereto, wobbler elements toward opposite ends ofand non-rotatable with the shaft, one for each setof cylinders, memberstoward opposite ends of and rotatable with the shaft and in theirrotation imparting movement to the wobbler elements, and pistonsreciprocatory in said cylinders and operatively connected with saidwobbler elements; the improvement which comprises two pairs ofcross-heads near to protect by4 Letters ,opposite ends of the shaft,slidable along, but

heldfrom rotation relative to, the said shaft, means, including screwthreads of dierent pitch engaging the two cross-heads of a pair, adaptedto move the two cross-heads of each pair simultaneously in the samedirection but to different distances, eachof saidrotatable membersVhaving a pivotal connection with one ofthe two cross-heads vat thecorresponding end' of the shaft, and connections between each rotatablemember and the other cross-head at the'correspending end of the shafteffective to change the .angle of the wobbler velement ywhen saidcross-heads are so moved. 2. Inan internal combustion engine comprisinga rotatable engine shaft, two sets of opposed cylinders disposed aboutsaid shaft and having to thereby admit a relatheir axes parallelthereto, wobbler elements toward opposite ends of and non-rotatable withthe shaft, one for each set of cylinders, rotatable members towardopposite ends of and rotatable with the shaft, pistons reciprocatcry insaid cylinders and operatively connected with said wobbler elements; theimprovement which comprises two pairs of sleeves, one pair at each ofthe opposite end portions of the shaft, slidable upon and rotatable withthe shaft, each of said rotatable members being pivotally connected withone sleeve of the pair of sleeves at the corresponding end portion ofthe shaft, a link connection between each of said rotatable members andthe other sleeve of the corresponding pair, and means including screwthreads of dierent pitch engaging the two sleeves of a pair, adapted tosimultaneously slide the corresponding two pairs of sleeves in oppositedirections while at the' same time sliding the two sleeves of each pairdifferent distances in the same direction.

3. In an internal 1combustion engine comprising a rotatableengine shaft,two setsI of opposed cylinders disposed about said shaft and havingtheir axes parallel thereto, wobbler elements toward opposite ends ofand non-rotatable with the shaft, one for each set of cylinders, memberstoward opposite ends of and rotatable with the s-haft and in theirrotation imparting wobbling movement to the wobbler elements, pistonsreciprocatory in said cylinders and operatively connected with saidwobbler elements; the improvement which comprises two .cross-headsslidable along, but held from rotation relatively to, said shaft, meansso pivotally connecting each rotatable member with both correspondingcrossheads that relative movement of said cross-heads along the shaftswings such rotatable member and its corresponding wobbler element tochange their angular position on the shaft, a second shaft extendingwithin the main shaft having near each end two threaded portionsengaging interior threads in the two cross-heads respectively, saidthreaded portions being of different pitch to thereby, when said secondshaft is rotated, move said cross-heads in the same direction but todifferent distances.

4. The construction defined in claim 3 in which said two threadedportions are of different` diameters so that the threaded portion ofsmaller diameter engaging one cross-head can enter the threaded interiorof the other cross-head without engaging the same.

5. The construction dened in claim 1 in which each rotatable member ispivotally connected at its center with one of the -correspondingcrossheads and in which the connection of such rotatable member with theother corresponding cross-head comprises a sleeve carried by the lastnamed cross-head and slidable on the shaft, an arm on the wobblerelement between its center and periphery, an arm on said sleeve, and alink -connectingsaid arms.

SAMUEL B. ECKERT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

